We know the K can't move into check, right? Other than that, he is very much capable of capturing just like any other piece. You must make sure that when you move a piece right next to your opponent's K to deliver check, that your piece is protected. That way the K can't take it because he would be placing himself in check, and that's a big no no. Does that help?
Question about King

It does help baddogno, thank you very much, but i'm still wondering, you know what? i think because the moves show you where you can or not, and maybe the bigger peaces don't show the grey dot, it should be something especially for newbe to really see what they can take or not. Maybe put a grey dot on top of the peaces and not under.
Thank you again

Hi! My name is Lauren Goodkind and I'm a chess coach based in California.
There are several ways a king can get out of check, depending on the position.
1) Capture the piece that is giving the check
2) Move the king to a square where it's not check.
3) Block the check with one of your pieces.
4) If it's double check (meaning that two of your opponent's pieces are checking the king), then the king must MOVE out of check.
I hope that this helps.

thank you much laurengoodkindchess
it helped a lot seriously, i hope i can keep adversaries away a little bit.
i will win
I know i should study more, but when i open chess.com i get the urge to play online.
I am still not sure why when you check the king, it is only forced to move a step away and other times can eat the peace next to it. what is the difference? Every time i move a peace next to it i think it will be able to move away only, instead he eats me nice and fresh.
Thank you